System of control



N. W. STORER.

SYSTM 0F CONTROL.-

APPLlcAUoN min ocr. t1. 191s.

UNITED STATES PATENT OFFICE.

NORMAN W. STORER, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR T0 WESTING- HOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENN- SYLVANIA.

p SYSTEM QF CONTROL.

Specification of Letters Patent.

Patented July 12, 1921.

To all 'whom t may concern:

Be it known that I, NORMAN W. S'ronnn, a citizen of the United States, and a resident of Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented a new and useful yImprovement in Systems of Control, of which the following is a speciication.

My invention relates to systems of control and particularly to the control of elec-- tric railway motors and the like when initiating regenerative conditions.

-One object of my invention is to provide a system of the above-indicated character which shall be exceedingly simple and inexpensive in construction, compared with pre vious systems for accomplishing the same results.

More specifically stated, it is the object of my invention to provide a relatively simple manually-governed addition to a control system, whereby regeneration, either when starting down a grade from rest or during a coasting period, may be rapidly and reliably initiated without requiring the use of automatic relays or other slmilar devices.

In connection with regenerative control of railway vehicles, itis desirable to start the train on. a down grade from rest with the master controlling apparatus inthe regenerative position, using a certain amount of power to accelerate the train from rest and then effecting a gradual transitionfrom motoring to regenerating. Furthermore, it is desirable to begin regeneration when the train is coasting, particularly if running down a heavy grade, without first applyingv a heavy accelerating current to the motors,

as has been done in some previous systems of the'type under consideration, which entailsy various disadvantages, in addition to loss of power. According to the present inventioinI provide a relativelysimple com1 trol system which is manually governed in a simple manner to achieve the above-mentionedpobjectsas hereinafter more fully set forth. f

My invention may best be understood" by reference to the accompanying drawing, wherein Figure 1 is a diagrammaticv view'of the main circuits of a system of control enrbodyingmy invention; Fig. 2 is a diagram maticview of auxiliary circuits yfor adjusting the main circuits that are shown in Fig. l; Fig. 3 is a sequence chart, of well-known form, indicating the preferred order of operationof the various switches of Fig. 1;-

and F ig.` 4 is a detail diagrammatic view ofk one of the unit switches that is employed in" the illustrated main circuits.

Referring to Fig. l of the drawings, the system here shown comprises suitable suppl -circuit conductors respectively marked 'lrolley and Ground;` a main dynamo electric machine having a commutator-type armature A and a field winding F of the series type; a variable main-circuit resistor l; a plurality of `switches Rl to R4, inclusive, for varying the active value of the resistor l; a plurality of circuit-arranging switches LS, M, RS and G; an axle-driven exciter or generator having an armature 2 that is either mounted upon, or mechanically connected with, the shaft 3 of the main armature A and further having a separately-excited field winding 4, the energization of which may be varied by a r suitable resistor y5; a main-4 circuit resistor 6 that is employed in conative conditions only; and a changeover switch C() of a familiar electrically-controlled drum type that is adapted to occupy either one of two positions, respectively corresponding to motoring and regenerating operation, as indicated by the abbreviations Mot. and Reg.

Referring to Fig. 2, the auxiliary governs ing system shown comprises the actuating coils of the various unit switches and for the changeover switch CO, together with a plurality ofv auxiliary contact members or interlocks that are either associated with, and actuated by, thek respectively designated unit switches in accordancev with the familiar construction that is illustrated in Fig. 4, or are located upon the changeover drum or the regenerative drum vforming a part ofy the master controller MCgand a battery B,

or other suitable source of energy, for supplying the auxiliary governing system.

The master controller is illustrated as comprising a drum or section 10, for gov-A adjust-ing contact members and a further contact member for varying the exciter'- ield-winding resistor 5.

Assuming that it is desired to effect regenerative operation of the main machine down a grade, starting from rest at the top thereof, the train operator rst actuates the regenerative drum to the illustrated on position, whereupon a circuit is established from the positive terminal of the battery B through conductors 1l and l2, control tingers 18 and 14, which are bridged by contact segment 15 of the regenerative drum, conductor 16, train-line conductor 17, conductor 18, actuating coil Beg. of the changeover drum and conductors 19, 20 and 21 to the negative terminal of the battery B. In this way, the changeover drum is moved to its illustrated position Reg. in a manner similar to the actuation of the familiar` electrically-controlled drum type reversing` switch from one position to another.

As soon as the regenerative drum occupies its illustrated on position, the master controller drum 10 may be thrown to its initial operative position c. to establish the exciting circuit for the main ield winding and to connect the main machine across the supply circuit by closing switches LS, M, RS and Gr in a manner to be subsequently described in detail. The main-armature circuit is thus established from the trolley through conductor 22, switch LS. main resistor 1, switch M, main armature A, switch RS, stabilizing resistor 6, conductors 23 and 24, contact segment 26 of the changeover drum in its regenerative position, conductor 27 and switch G to ground.

The exciting or main-eld-winding circuit is established from the positive terminal of the axle-driven armature 2 through conductor 23, resistor 6, switch RS, conductor 28, main field winding F, conductor Q9 and contact segment 30 of the changeover switch to the negative terminal of the exciting armature.

lVhen the train is assumed as starting from rest, there is, of course, originally no voltage in the axle-driven exciter circuit and, consequently, the main current traversing the armature of the propelling motor from the trolley will be divided between the parallel circuits respectively includingr the sta.- bilizing resistor G and the main el d winding F together with the exciter armature 2, in the inverse ratio of the resistances of these branch circuits. By providing the stabilizing resistor with from 30% to 40% or' the resistance of the field-winding branch, the proportion of current passing through that branch will reach from 20% to 30% of the armature current. Such a degree of excitation will be ample to accelerate the train on the down grade and. as soon as the train begins to move, the voltage of the exciter armature which, as illustrated, is separately excited by a suitable source, such as the battery B, will increase directly with the speed, thereby gradually strengthening the iield ot the main motor until, by the time the accelerating resistor 1 is excluded from circuit by the manipulation or the master controller, as hereinafter described, the main field will be of full strength, and the generated vol"- age ot the main armature will be approximately equal to the line voltage, thus rendering the transiter trom motoring to regenerating action extremely smooth and easy. @nce regeneration has started, the proper relation of exciting voltage to suppl \'cireuit voltage to control the vehicle speed may be readily secured by manipulating the regenerative drum in the manner to be described in connection with Fig. 2.

lVith the master-controller section 10 occupying position a., a circuit is continued from the positively energized conductor ll through control lingers and 3G, which are bridged by contact segment 3T, conductor 38 and ,junction point 39, where the circuit divides, one branch including conductor i0, contact segment -fll ot the regenerative drum, conductor a2, train-line conductor 4?), couductor 4st, actuating coil ot the switch BS, interlock LS-out and 'contact segment CO-Reg. to the negative conductor 10, and the other branch traversing conductor L15, train-line conductor a0, conductor 4T, actuating coil ot the line switch LS, contact segment 4S of the regenerative drum, conductor 40, ,interlock B-S-in (as soon as that switch has closed) and contact member CO-Beg. to the negative conductor 19.

Further circuits are completed from the train-line conductor #i6 through conductors 50 and 51 to the actuating coils of the switches G and M, respectively.

The above-traced exciting and regenerating circuits are thus established by the closure of the switches LS, M, RS and (al, as indicated in step c ot the sequence chart and, as the vehicle gains in speed, the master controller section 10 may be gradually operated through its successive positions to e, inclusive, whereby control lingers 52 to 55, inclusive, are respectively engaged by the contact segment 37 to complete the energizing circuits for the actuating coils of the switches R1, B2, B3 and Ba and thus shortcircuit the accelerating resistor l in a gra dual manner.

As stated above, the transition from motoring to regeneration will occur at about this time and further regulation et the regenerative action may be effected by moving the regenerative drum through its successive positions 0 to s, inclusive, whereby the exciter-field-circuit resistor 5 is gradually short-circuited to increase the volt-age of the axle-driven exciter, thereby serving to mainlimxw tain thefdesired `vehicle speed onthe down grade or to compensate forthe gradual decreaseof vehicle speed in case the train is operating on a substantially level stretch of track. v i

When startingi regeneration during a coasting period, the procedure yis the same, so -far as the manual operation. is concerned, but, since the train is 1n motion, the exciter voltage will-be .built up and the main field strength will be 'established practically as soon as the above-described connections are firstmade. l When the4 master controller is thrown to its first operating position to connect the main machine to the supply circuit with the resistorl in series relation to the main armature, a relatively small'current will, in general, vflow through the circuit, depending in value upon the electromotive force generated inthe main armature. It is preferable to begin operation withaa relatively weak field strength in order to prevent the possibility of an excess voltage being f generated fin the amature. in case the train isk operating at a very high speed.; Inany case, however, the current traversing the motors and the main resistor 1 willbe so small as to have `afvery slightv effect upon thetrain, thus preventing any sudden application of braking effort. Moreover, the train yoperator may be informed asto whether the locomotive is motoring or regenerating by means of an ammeter in the cab. If the main machine .isr motoring, the operator should adjust the excitation of the exciter vfield Windingy by the previouslyfdescribed manipulation of the regenerative drum, until the ammeter indicates that current is flowing into the trolley conductor, thus showing that regeneration has begun. The main resistor 1 may then be excluded from circuit and the vehicle speed controlled by the methods already explained.

The auxiliary circuits not described so far relate to motoring operation of the main machine and, inasmuch as the present-invention is concerned chiefly with regenerative operation, only a brief description of such circuits will be necessary.

When the regenerative drum is thrown to its off position, one circuit is established from the sitively-energized battery conductor 12 t rough conductor 62, contact segment 63 of the regenerative drum, conductor 64, train-line conductor 65, conductor 66 and the actuating coil Mot. of the changeover drum, whereby the drum is actuated to its position indicated in Fig. 1 by the dotted line marked Mot The switch RS cannot be closed under such conditions by reason of the exclusion from its actuating-coil circuit of the contact segment CO-Reg., while the governing circuit for the line switch LS is now continued from the actuating coil thereof through contact se ent 67 of the regenerative drum yin its o 7 position, interlock RSoutand contact'SegmeIlt (lO-Mot. Otherwise, the auxiliary circuits are the same as previously described.

. The main circuits, during motor conditions, maybe traced as follows: from the trolley through conductor 22, line switch LS, main resistor 1, switch M, main armature A, conductor 28, main field Winding F, conductor 29, contact segment 30 of the changeover drum, conductor 27 and switch G to ground.- Under motoring conditions, therefore, the axle-driven exciter is not utilized for energizing the main field winding, but, if desired, may be employed for other vpurposes on the locomotive, such as charging storage batteries, furnishing power for lights, etc.

It will be seen that I have thus provided a method of starting regeneration of a train down grade from rest or during the coasting period, withall regenerative connections manually made without the use of automatic relaysor other devices'dependent uponcurrent or voltage conditions.

Iv desire it to'be understood that, in the present specification and claims, the term =manually. is used as the opposite of the -term automatically, in `other words, I refer to the 'manual control of main-circuit apparatus .through the master controller, whereby the machine operation is always under the control of the train operator.

It will be appreciated that the above-describedregenerative connections are presented for illustrative purposes only, and that my invention may readily be applied to other types of connections. The preferred form, however, is that illustrated, a complete exposition of which is contained in a co-pending application of R. E. Hellmund, Serial No. 44,443, filed Aug. 9, 1915, and assigned to the Westinghouse Electric and Manufacturing Company.

Consequently, I do not wish to be restricted to the specific circuit connections or arrangement of parts herein set forth, as various modifica-tions thereof may be made without departing from the spirit and scope of my invention. I desire, therefore, that only such limitations shall be imposed as are indicated in the appended claims.

I claim as my invention:

1. In a system of electric-vehicle control, the combination with a supply circuit and a dynamo-electric machine having an armature and a field winding, of means for initiating regenerative braking of the vehicle from rest down a grade including the manual establishment of exciting connections for said field winding and the manual connection of a high-resistance circuit including said machine across the supply circuit, and means for excluding resistance from the machine circuit as the vehicle speed increases to effect the transition to regeneration under certain speed conditions7 as determined by the exciting-circuit and the supply-circuit voltages. Y

2. The method of initiating regeneration of a momentum-driven dynamo-electric machine that consists in establishing an exciting circuit and 'directly and manually connecting the machine to the supply circuit, initially inserting a resistor in the machine circuit to limit the motoring current to a relatively low value, and gradually shortcircuiting said resistor to effect the transition to regeneration under certain speed condit-ions7 as determined by the exciting-circuit and the supply-circuit voltages.

3. In a system of electric-vehicle control, the combination with a supply circuit and a dynamo-electric machine having an armature and a field winding, of a vehicle-axledriven generator for energizing the machine field Winding, a source of energy for separately exciting said generator, direct and manual means for initiating regenerative braking of the vehicle including the completion of the generator circuits and the connection of a high-resistance circuit including t-he machine across the supply circuit,`and means for excluding resistance from the machine circuit to effect the transition to regeneration, as determined by the generator and the supply-circuit voltages.

4. In a. system of electric-vehicle control, the combination with a supply circuit and a dynamo-electric machine having an armature and a field winding, of a vehicle-axledriven generator for energizing the machine field Winding, a source of energy for separately exciting said generator, a resistor, and a. controller for manually electing the connectionY of the generator to said field winding and of the machine and the resistor in series relation across the supply circuit, said controller being also adapted to exclude said resistor from the machine circuit to effect the transition to regeneration, as determined by the generator and the supply-circuit voltages and adapted to vary the separate excitation of said generator.

5. In a system of electric-vehicle control, the combination with a supply circuit and a propelling dynamo-electric machine having a series-type field Winding, of a vehicleaxle-driven generator for energizing the machine field Winding during regeneration in the same direction as when the machine is motoring, an accelerating resistor, and a controller for manually effecting the connection of the generator to said ield Winding and of the machine and the accelerating resistor in series relation across the supply circuit, said controller being also adapted to exclude said resistor from the machine circuit to effect the transition to regeneration, as determined by the generator and the supply-circuit voltages and adapted to vary the excitation of said generator at Will.

In testimony whereof, I have hereunto subscribed my name this 3rd day of Oct.

NORMAN W. STORER; 

